Recently, a drive recorder becomes popular as described in PTL 1. Such a drive recorder captures and records an image around a vehicle when a driver encounters a traffic accident or a situation (incident) that might lead to the traffic accident during driving of the vehicle.
More specifically, the drive recorder includes a camera that images a situation in front of the vehicle, and records an image captured by the camera in a recording unit when vehicle acceleration detected by an acceleration sensor exceeds an upper limit (that is, when the behavior of the vehicle changes drastically). For example, the recorded image data is used for investigating the cause of an accident in an automobile insurer, or used in the safe driving education of employees (that is, drivers) in a transport service provider.